Related Experiment Videos
Skeletal muscle size: relationship to muscle function in heart failure
1Cardiology Section, Veteran Affairs Medical Center, San Francisco, California.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 1, 1993
Summary
Congestive heart failure (CHF) patients exhibit smaller thigh muscle size, impacting exercise capacity. However, the force generated per muscle area remains unaffected, suggesting atrophy rather than intrinsic muscle weakness.
Area of Science:
- Cardiology
- Exercise Physiology
- Skeletal Muscle Biology
Background:
- Skeletal muscle dysfunction is prevalent in congestive heart failure (CHF) patients, contributing to exercise intolerance.
- Skeletal muscle atrophy is a potential mechanism underlying these functional deficits.
Purpose of the Study:
- To investigate skeletal muscle size and function in CHF patients compared to healthy controls.
- To determine the relationship between muscle size and muscle strength/endurance in CHF.
Main Methods:
- Magnetic resonance imaging (MRI) to measure thigh muscle cross-sectional area (MCSA).
- Isometric strength testing and isokinetic dynamometry for muscle function assessment.
- Comparison between 21 CHF patients and 12 age/sex-matched sedentary controls.
Main Results:
- CHF patients had significantly smaller thigh and knee extensor MCSAs compared to controls, even after normalizing for body size.
- Isometric strength was not significantly different, but muscle endurance was markedly impaired in CHF patients.
- A strong correlation existed between knee extensor MCSA and isometric strength, but not with dynamic endurance.
Conclusions:
- Skeletal muscle atrophy is present in CHF patients.
- Maximal force generated per unit of muscle area is preserved, indicating that muscle quality is not impaired.
- Muscle atrophy contributes to exercise limitation in CHF, particularly affecting endurance more than maximal strength.